随机生成四则运算题目

import javax.swing.*;
public class YunS {
    public  static void main(String[] args){
        int a[]=new int[30];//第一个数的分子
        int b[]=new int[30];//第一个数的分母
        int c[]=new int[30];//用于判断加减乘除号
        int d[]=new int[30];//第二个数的分子
        int e[]=new int[30];//第二个数的分母
        String f[]=new String[30];//答案
        for(int i=0;i<30;i++)
        {
            a[i]=(int)(Math.random()*100+1);
            b[i]=(int)(Math.random()*100+1);//分母不能为0
            int n=MaxCommonDivisor(a[i],b[i]);
            
            c[i]=(int)(Math.random()*100);
            
            d[i]=(int)(Math.random()*100+1);
            e[i]=(int)(Math.random()*100+1);//分母不能为0
            int m=MaxCommonDivisor(d[i],e[i]);
            //加法运算
           if(c[i]>=0&&c[i]<25) {
                if(n==b[i]&&m==e[i])
                {System.out.println(a[i]/b[i]+"+"+d[i]/e[i]+"=");f[i]=(a[i]/b[i])+(d[i]/e[i])+"";}
                else if(n==b[i]&&m!=e[i])
                {System.out.println(a[i]/b[i]+"+"+d[i]/m+"/"+e[i]/m+"=");
                f[i]=(a[i]/b[i])*(e[i]/m)+d[i]/m+"/"+e[i]/m;}
                else if(n!=b[i]&&m==e[i])
                {System.out.println(a[i]/n+"/"+b[i]/n+d[i]/e[i]+"=");
                f[i]=a[i]/n+(d[i]/e[i])*(b[i]/n)+"/"+b[i]/n;}
                else if(n!=b[i]&&m!=e[i])
                {System.out.println(a[i]/n+"/"+b[i]/n+"+"+d[i]/m+"/"+e[i]/m+"=");
                int k=MaxCommonDivisor(a[i]*e[i]+b[i]*d[i],b[i]*e[i]);
                if(k==b[i]*e[i])
                f[i]=(a[i]*e[i]+b[i]*d[i])/k+"";
                else if(k!=b[i]*e[i])
                f[i]=(a[i]*e[i]+b[i]*d[i])/k+"/"+b[i]*e[i]/k;
                }
            }
            //减法运算
            else if(c[i]>=25&&c[i]<50) {
                if(n==b[i]&&m==e[i])
                {System.out.println(a[i]/b[i]+"-"+d[i]/e[i]+"=");f[i]=(a[i]/b[i])-(d[i]/e[i])+"";}
                else if(n==b[i]&&m!=e[i])
                {System.out.println(a[i]/b[i]+"-"+d[i]/m+"/"+e[i]/m+"=");
                f[i]=(a[i]/b[i])*(e[i]/m)-d[i]/m+"/"+e[i]/m;}
                else if(n!=b[i]&&m==e[i])
                {System.out.println(a[i]/n+"/"+b[i]/n+"-"+d[i]/e[i]+"=");
                f[i]=a[i]/n-(d[i]/e[i])*(b[i]/n)+"/"+b[i]/n;}
                else if(n!=b[i]&&m!=e[i])
                {System.out.println(a[i]/n+"/"+b[i]/n+"-"+d[i]/m+"/"+e[i]/m+"=");
                int k=MaxCommonDivisor(a[i]*e[i]+b[i]*d[i],b[i]*e[i]);
                if(k==b[i]*e[i])
                f[i]=(a[i]*e[i]-b[i]*d[i])/k+"";
                else if(k!=b[i]*e[i])
                f[i]=(a[i]*e[i]-b[i]*d[i])/k+"/"+b[i]*e[i]/k;
                }
            }
            //乘法运算
            else if(c[i]>=50&&c[i]<75)  {
                if(n==b[i]&&m==e[i])
                {System.out.println(a[i]/b[i]+"X"+d[i]/e[i]+"=");f[i]=(a[i]/b[i])*(d[i]/e[i])+"";}
                else if(n==b[i]&&m!=e[i])
                {System.out.println(a[i]/b[i]+"X"+d[i]/m+"/"+e[i]/m+"=");
                int k=MaxCommonDivisor(a[i]/n*d[i],e[i]);
                if(k==e[i])
                f[i]=a[i]*d[i]/n/e[i]+"";
                else if(k!=e[i])
                    f[i]=a[i]*d[i]/n/k+"/"+e[i]/k;
                }
                else if(n!=b[i]&&m==e[i])
                {System.out.println(a[i]/n+"/"+b[i]/n+"X"+d[i]/e[i]+"=");
                int k=MaxCommonDivisor(a[i]*d[i]/m,b[i]);
                if(k==b[i])
                    f[i]=a[i]*d[i]/m/b[i]+"";
                    else if(k!=e[i])
                        f[i]=a[i]*d[i]/m/k+"/"+b[i]/k;}
                else if(n!=b[i]&&m!=e[i])
                {System.out.println(a[i]/n+"/"+b[i]/n+"X"+d[i]/m+"/"+e[i]/m+"=");
                int k=MaxCommonDivisor(a[i]*d[i]/m/n,b[i]*e[i]/m/n);
                if(k==b[i]*e[i]/m/n)
                f[i]=a[i]*d[i]/b[i]/e[i]+"";
                else if(k!=b[i]*e[i]/m/n)
                f[i]=a[i]*d[i]/k/m/n+"/"+b[i]*e[i]/k/m/n;
                }
            }
            //除法运算
            else if(c[i]>=75&&c[i]<100)   {
                if(n==b[i]&&m==e[i])
                {System.out.println(a[i]/b[i]+"÷"+d[i]/e[i]+"=");f[i]=(a[i]/b[i])/(d[i]/e[i])+"";}
                else if(n==b[i]&&m!=e[i])
                {System.out.println(a[i]/b[i]+"÷"+d[i]/m+"/"+e[i]/m+"=");
                int k=MaxCommonDivisor(a[i]/n*e[i],d[i]);
                if(k==d[i])
                f[i]=a[i]*e[i]/n/d[i]+"";
                else if(k!=d[i])
                    f[i]=a[i]*e[i]/n/k+"/"+d[i]/k;
                }
                else if(n!=b[i]&&m==e[i])
                {System.out.println(a[i]/n+"/"+b[i]/n+"÷"+d[i]/e[i]+"=");
                int k=MaxCommonDivisor(a[i]*m,b[i]*d[i]);
                if(k==b[i]*d[i])
                    f[i]=a[i]*m/b[i]/d[i]+"";
                    else if(k!=b[i]*d[i])
                        f[i]=a[i]*m/k+"/"+b[i]*d[i]/k;}
                else if(n!=b[i]&&m!=e[i])
                {System.out.println(a[i]/n+"/"+b[i]/n+"÷"+d[i]/m+"/"+e[i]/m+"=");
                int k=MaxCommonDivisor(a[i]*e[i],b[i]*d[i]);
                if(k==b[i]*d[i])
                f[i]=a[i]*e[i]/b[i]/d[i]+"";
                else if(k!=b[i]*d[i])
                f[i]=a[i]*e[i]/k+"/"+b[i]*d[i]/k;
                }
            }
            
        }
        System.out.println("答案：");
        for(int i=0;i<30;i++)
            System.out.println(f[i]);
    }
    //求两个数的最大公约数
    public static int MaxCommonDivisor(int m,int n){
        if(m<n){int temp=m;m=n;n=temp;}
        while(m%n!=0){
            int temp=m%n;
            m=n;
            n=temp;
        }
        return n;
    }
}

运行结果：

      

编程思路：主要利用了产生随机数的方法和求最大公约数将分数约分的方法。先利用产生的随机数，根据不同的数据范围确定加减乘除，再产生4个随机数，分别作为第一个数和第二个数的分子和分母，再求分子分母的最大公约数进行约分，进行加减乘除后的分数再次进行约分。